ZingPath: Chemical Bonding

What is frequency? How is it measured? What is the relationship between frequency and the energy of an electromagnetic wave?

~ Frequency refers to the number of waves that pass through a point per second and is measured in hertz. Frequency and the energy of an electromagnetic wave are directly proportional. If frequency is high, then energy is high, too. German physicist Max Planck stated that the energy of an electromagnetic wave can be calculated by multiplying the frequency by a constant, which he named Planck's constant.

What is wavelength? What is the difference between radio waves and gamma rays? What is the relationship between wavelength and frequency?

~ Wavelength is the distance between two consecutive similar points. On the electromagnetic spectrum, radio waves have the greatest wavelength and gamma rays have the smallest wavelength. Wavelength and frequency are inversely related. As wavelength increases, frequency decreases, and as wavelength decreases, frequency increases.

What is the relationship among electromagnetic waves, frequency, and wavelength?

~ We know that frequency multiplied by the wavelength is equal to the speed of the electromagnetic wave. The speed of electromagnetic waves is constant and equal to the speed of light.

Using the speed of light (3 × 108 m/s), calculate the wavelength of light that has a frequency of 5.1 × 1015.

~ Using the formula c = lf

3 × 108 m/s = l × 5.1 × 1015 s-1

l = 3 × 108 m/s/5.1 × 1015

l = 5.8 × 10-8 m

Using the speed of light (3 × 108 m/s), calculate the frequency of light with a wavelength of 7.3 × 10-15 m.

~ Using the formula c = lf

3 × 108 m/s = 7.3 × 10-15 m × f

f = 3 × 108 m/s/7.3 × 10-15 m.

f = 4.1 × 1022 m

Using the formula E = hc/l, calculate the energy in Joules per photon of light with a wavelength of 3.9 × 10-10m. Remember, the speed of light is 3 × 108 m/s and Planck's constant is 6.62 × 10-34 Js.

~ E = hc/l

E = (6.62 × 10-34 Js*3 × 108 m/s)/ 3.9 × 10-10m

E = 5.1 × 10-16 J/photon